Refrigeration Device

ABSTRACT

A refrigeration device has a cabinet having a pair of refrigerated interior spaces and an upper compartment which houses removable compressor and evaporator modules. An air supply plenum is positioned between the refrigerated spaces to evenly provide cold air. The evaporator module has a removable, thermally insulative cover to facilitate servicing.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to refrigeration devices, such asrefrigerators and freezers, and more particularly, to high performancerefrigerators and freezers permitting close control of temperature.

2. Brief Description of Related Art

High performance refrigerators and freezers are employed in environmentsin which materials must be stored at controlled low temperatures, suchas in scientific laboratories, pharmacies and hospitals. Such materialsinclude samples of tissues, chemical reagents, vaccines, cell lines,plasma, blood, and other biological materials. Materials stored inrefrigerators and freezers intended for domestic and commercial usefrequently experience significant temperature fluctuations which areundesirable in scientific and medical contexts, as such fluctuations mayresult in the degradation of stored materials.

High performance refrigerators may include mechanisms for minimizingtemporal and spacial temperature fluctuations. For example, U.S. Pat.No. 9,310,121, incorporated herein by reference, discloses a highperformance refrigerator including a sacrificial evaporation whichoperates to avoid a temperature spike which would otherwise occur duringa defrost cycle. Similarly, U.S. Publication 2013/0098075 A1,incorporated herein by reference, discloses a high performancerefrigerator having an evaporator outside the refrigerated interior, anda eutectic member configured to melt at the operating temperature of therefrigerator. During a defrost cycle, the eutectic solidifies,withdrawing heat from the interior compartment.

Failure of a refrigeration device can result in significantinconvenience and/or a significant financial loss. Refrigeration devicesinclude mechanical components required to transfer heat from within thecontrolled interior space to the exterior. Mechanical devices such ascompressors and fans, may be designed for an extensive service life, butare subject to wear, and will ultimately fail. Frequently, the failedcomponents can be replaced and the refrigeration circuit can berecharged with a refrigerant fluid. However, replacement can requiresignificant time, during which the contents must be transferred toanother refrigeration device or lost. In a domestic or commercialcontext, another refrigeration device is simply not available. In amedical, pharmacy or hospital context, such mechanical failures canresult in the loss of critical, irreplaceable materials. Thus, there isa need for a refrigeration device which can be quickly and easilyrepaired in the event of a failure of a mechanical component, and whichprovides even temperature distribution and close control of temperature.

U.S. Pat. Nos. 5,953,929 and 6,070,424, each incorporated herein byreference, disclose a modular refrigeration unit intended forinstallation in a variety of different refrigerators and freezers,rather than installing each of the individual components of therefrigeration system separately in each such refrigerator or freezer.Similarly, U.S. Pat. No. 6,701,739, incorporated herein by reference,discloses a modular refrigeration system for a refrigeration appliancewhich is removable and replaceable in the event of the failure of acomponent of the system, such as the compressor or the condenser. U.S.Pat. No. 5,009,081, incorporated herein by reference, discloses amodular mechanical refrigeration unit which is relatively thin and isadapted to form one wall of a refrigeration appliance.

U.S. Pat. No. 6,209,342, incorporated herein by reference, discloses anevaporator housing for a refrigerator located between a refrigeratorcompartment and a freezer compartment. U.S. Patent Publication2012/0152499, incorporated herein by reference, discloses an evaporatorincluding a housing, a coil assembly, and a replaceable fan module. U.S.Pat. No. 5,878,592, incorporated herein by reference, discloses anevaporator housing for refrigerated transportation vehicles. U.S. Pat.No. 6,240,739, incorporated herein by reference, discloses an evaporatorcover for a display refrigerator. U.S. Pat. No. 6,145,336, incorporatedherein by reference, discloses a plastic mount for an evaporator for usein ice making machines. U.S. Pat. No. 6,134,909, incorporated herein byreference, discloses a housing for physically and thermally isolatingthe evaporator section of an air conditioning unit that is mounted onthe cabin roof of a trailer or van. U.S. Pat. No. 4,086,785,incorporated herein by reference, discloses a two piece fan motor mountfor a domestic refrigerator. U.S. Pat. No. 3,599,442, incorporatedherein by reference, discloses a unitary fan evaporator assembly.

SUMMARY OF THE INVENTION

The present invention provides a refrigeration device comprising acabinet having at least one refrigerated interior space and, in onepresently preferred embodiment, a first refrigerated interior space anda second refrigerated interior space.

The cabinet also includes a compartment, which preferably houses atleast one component of the refrigeration system used to remove heat fromthe first and second refrigerated interior spaces.

The refrigeration device also includes an air supply plenum to deliverrefrigerated air to the at least one refrigerated interior space. In apresently preferred embodiment, the air supply plenum is positionedbetween the first and the second refrigerated spaces. This centrallydisposed plenum advantageously delivers cooling air to all internalcorners of the refrigerated interior spaces.

Preferably, the compartment includes a compressor module and anevaporator module, with a refrigerant fluid circulating between thecompressor module and the evaporator module. Preferably, the compressormodule is removable as a unit from the refrigeration device. It is alsopreferred that the compressor module be replaceable as a unit from therefrigeration device.

Further, it is preferred that the evaporator module is removable as aunit from the refrigeration device. It is also preferred that theevaporation module be replaceable as a unit from the refrigerationdevice.

The air supply plenum is adapted to provide air from the evaporatormodule to at least one refrigerated space.

In a presently preferred embodiment, the air supply plenum is adapted toprovide air from the evaporator module to the first refrigeratedinterior space and the second refrigerated interior space.

The evaporator module preferably includes an evaporator and at least onefan for circulating air from the evaporator through the air supplyplenum. Preferably, the evaporator module includes a removable cover,the removable cover permitting access to at least one component of therefrigeration system, such as an evaporator and/or an evaporator fan.

The refrigeration device also includes at least one return air plenumfor collecting air from the first and the second refrigerated spaces forsupply to the evaporator module.

In one presently preferred embodiment, the compartment is positionedabove the first and second refrigerated interior spaces. In anotherembodiment, the compartment is positioned below the first and the secondrefrigerated spaces.

Preferably, the removable cover is formed from a thermally insulativematerial. Preferably, the thermally insulative material is an expandedpolymeric material. Preferably, the expanded polymeric material is anexpanded polypropylene. Preferably the thermally insulative material hasthermal conductivity of less than 0.041 W/m-K at 24 degrees C.Preferably, the thermally insulating material is also elastic to providea reusable seal without the need for any caulking, sealant, gaskets, orfasteners. Preferably, the thermally insulating material possessesflame-retardant properties. Preferably, the thermally insulatingmaterial includes anti-microbial agents. Preferably, the expandedpolymeric material has a density of from about 46 to 81 g/L.

Preferably, either the compressor module or the evaporator module can beremoved and replaced without having to discharge and recharge therefrigerant fluid which circulated between the compressor module and theevaporation module during operation of the refrigeration device.

Preferably, refrigerant is circulated between the compressor module andthe evaporator module through self-sealing dry-break couplings.Preferably, each of the compressor module and the evaporator moduleinclude a portion of at least one self-sealing dry-break coupling whichmatingly engages with a corresponding portion of a correspondingself-sealing dry-break coupling on the other module.

Preferably, the evaporator module includes a shroud over the evaporatorto prevent air returning from the first and second refrigerated spacesfrom bypassing the evaporator.

Preferably, the evaporator module includes return air supply ducts toprovide balanced air from at least one return air plenum to theevaporator.

Preferably, the interior surfaces of the return air supply ducts and theremovable cover are contoured to facilitate low air-side pressure dropthrough the evaporator.

Preferably, the evaporator module includes an upstanding partialenclosure for mating and sealing engagement with the removable cover.

Preferably, the compartment includes a mounting surface for thecompressor module and the evaporator module, the upstanding partialenclosure of the evaporator module contacting the mounting surface anddefining a contact area, the mounting surface being partially perforatedin the vicinity of the contact area to enhance the thermal isolation ofthe evaporator module.

Preferably, the compartment is generally thermally insulated from the atleast one interior refrigerated space, and the interior of theevaporator module is preferably generally thermally insulated from theinterior of the compartment.

Preferably, the evaporator module includes at least one locking devicefor securing the cover over the evaporator. Preferably, the at least onelocking device secures the cover to the upstanding partial enclosure.Preferably, cover is secured to the partial enclosure by a snap fit.Preferably, the cover is secured to the partial enclosure through aseparable seam having an air seal. Preferably, the refrigeration devicefurther includes at least one switch indicating when the cover is notsecurely fastened.

Preferably, the refrigeration device includes at least one alarm forsensing the temperature of the at least one interior refrigerated space,and providing a sensible indication, such as a visible or audibleindication, when the temperature has risen above a predetermined upperlimit temperature. Preferably, the refrigeration device includes atleast one alarm for sensing the temperature of the at least one interiorrefrigerated device, and providing a sensible indication, such as avisible or audible indication, when the temperature has fallen below apredetermined lower limit temperature.

Preferably, the refrigeration device includes a recording device formonitoring at least one temperature inside the at least one interiorrefrigerated space and recording the at least one temperature.

Preferably, the refrigeration device includes a control unit forcontrolling at least one aspect of the operation of the refrigerationdevice.

In another aspect, the present invention provides a double doorrefrigeration device comprising a cabinet having a first and a secondrefrigerated interior space, preferably of generally equal volume, morepreferably of equal volume. The cabinet includes a compartment forenclosing a refrigeration system including a compressor, a condenser,and an evaporator. An air supply plenum is positioned between the firstand the second refrigerated spaces, and is adapted to provide air fromthe evaporator to the first and the second refrigerated spaces. At leastone return air plenum is provided for collecting air from the first andthe second refrigerated spaces and returning the air to the evaporator.Preferably, the compartment is positioned above the first and secondrefrigerated interior spaces. Preferably, the compartment has aninterior, and the evaporator is positioned in a thermally insulativehousing within the compartment. Preferably, the housing includes aremovable cover. Preferably, the housing includes a shroud over theevaporator to prevent air returning from the first and secondrefrigerated spaces from bypassing the evaporator. Preferably, thehousing includes return air supply ducts to provide balanced air from atleast one return air plenum to the evaporator. Preferably, the interiorsurfaces of the return air supply ducts and the removable cover arecontoured to facilitate low air-side pressure drop. Preferably, thehousing includes an upstanding partial enclosure for mating and sealingengagement with the removable cover. Preferably, the compartmentincludes a mounting surface for the compressor and the housing, theupstanding partial enclosure of the housing contacting the mountingsurface and defining a contact area, the mounting surface beingpartially perforated in the vicinity of the contact area to enhance thethermal isolation of the evaporator.

In yet another aspect, the present invention provides a self-containedevaporator module for use with a refrigeration device. The evaporatormodule includes an evaporator module housing and an evaporator. Theevaporator module preferably includes at least one evaporator fan fordrawing or pushing air through the evaporator to cool the air flowingthrough the evaporator. The evaporator module housing preferablyincludes an evaporator module base and an evaporator module cover.Preferably, the evaporator module base and evaporator module cover fittogether tightly to provide a good seal against air flow between theinterior of the evaporator module and the exterior. Preferably, theevaporator module cover is formed from a thermally insulating material.Preferably, the evaporator module base is formed from a thermallyinsulating material. Preferably, the thermally insulating material isalso elastic to provide a reusable seal without the need for anycaulking, sealant, gaskets, or fasteners. Preferably, the thermallyinsulating material possesses flame-retardant properties. Preferably,the thermally insulating material includes anti-microbial agents.Preferably, the interior of the evaporator module is divided into a warmair chamber and a cold air chamber. Preferably, the warm air chamber andthe cold air chamber are separated by at least one interior wall formedin the housing and by the evaporator. More preferably, the warm airchamber and the cold air chamber are separated by the evaporator, and apair of interior walls formed in the housing. Preferably, the pair ofinterior walls is symmetrically disposed on either side of theevaporator. Preferably, the pair of interior walls and the inner surfaceof the evaporator housing form a shroud enclosing the cold air chamberand separating the cold air chamber from the warm air chamber.Preferably, the interior walls seal the cold air chamber when theevaporator module base is securely covered with the evaporator modulecover. Preferably, the warm air chamber extends along the width of afirst end of the evaporator housing, and back to a second end of theevaporator housing symmetrically along either side of the evaporatorhousing, on the outside of the interior walls of the housing.Preferably, a pair of warm air supply apertures is formed in theevaporator housing base proximate the second end of the evaporatorhousing within the warm air chamber. Preferably, a cold air supplyaperture is formed in the evaporator housing base generally centeredwithin the cold air chamber. Preferably, the interior walls of theevaporator housing are formed from a pair of first upper and lowershroud walls and a pair of second upper and lower shroud walls, thefirst and second upper shroud wall being formed integrally with theevaporator housing cover, and the first and second lower shroud wallbeing formed integrally with the evaporator cover base.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front elevational view of a refrigeration device accordingto the present invention, shown with the doors closed.

FIG. 2 is a perspective view of the refrigeration device of FIG. 1 asseen from the front lower right, with the doors removed to reveal theinterior.

FIG. 3 is a perspective view of the refrigeration device of FIG. 1 asseen from the front upper right, with the upper compartment coverremoved to reveal the interior of the upper compartment.

FIG. 4 is a top plan view of the refrigeration device of FIG. 1 shownwith the upper compartment cover removed to reveal the interior of theupper compartment.

FIG. 5 is a top plan view of the refrigeration device of FIG. 1 shownwith the upper compartment cover removed and the replaceable evaporatormodule removed to show the floor of the upper compartment under theevaporator module.

FIG. 6 is a perspective view of the compressor module of therefrigeration device of FIG. 1 shown removed from the refrigerationdevice.

FIG. 7 is a perspective view of the evaporator module of therefrigeration device of FIG. 1 shown removed from the refrigerationdevice with the cover rotated for removal to show the interior of theevaporator module and the interior detail of the cover.

FIG. 8 is another upper perspective view of the evaporator module shownin FIG. 7.

FIG. 9 is a perspective view of the evaporator module shown with thecover lifted off to reveal the interior of the module.

FIG. 10 is a partial perspective view of the refrigeration device ofFIG. 1 shown from below with the central plenum removed and one of thewarm air plenums partially removed.

FIG. 11 is a top plan view of the evaporator module shown in FIG. 7shown with the evaporator cover and evaporator fan removed.

FIG. 12 is a perspective view of the refrigeration device of FIG. 1 asseen from the front lower right, with the doors, upper compartmentwalls, condenser module, and evaporator cover removed.

DETAILED DESCRIPTION

As used in the present specification and claims “refrigeration device”means a refrigerator or freezer.

The present invention provides a refrigeration device which can bequickly repaired in the event of a failure of a mechanical component.

The present invention also provides double-door refrigeration deviceswith central air flow distribution. Double-door refrigerators have acentral partition or mullion that the doors close and seal upon. Thepresent invention advantageously uses this natural partition to evenlysupply cooling air to all internal corners of the refrigerated storagecabinet or interior spaces.

The present invention also evenly returns warm air through air ducts tothe evaporator coil while maximizing air flow to the evaporator. Thepresent invention provides an airflow design which maximizes evaporatorcoil heat exchange area with proper cross-sectional area for airflowwhile maintaining maximum refrigerated storage space.

In the present invention two separately replaceable modules areprovided, a compressor module and an evaporator module. The two modulestogether provide all the components of the refrigeration system for therefrigeration device. The compressor module includes a compressor, acondenser, a condenser fan, and associated lines for transferringrefrigerant fluid, as well as self-sealing dry-break couplings forconnecting refrigerant lines to the evaporator module. The evaporatormodule includes an evaporator, an evaporator fan, and associated linesfor transferring refrigerant, as well as self-sealing dry-couplings forconnecting refrigerant lines to the compressor module. The compressormodule and the evaporator module are housed in an upper compartment ofthe refrigeration device, and are mechanically attached to the floor ofthe upper compartment. The evaporator module is thermally isolated fromthe floor and the interior of the upper compartment. An easily removablethermally isolating cover is provided for the evaporator module toprovide access to the evaporator and evaporator fan.

Referring now to the figures in which like reference numerals representlike elements in each of the several views, there is shown in FIG. 1 afront elevation view of a presently preferred embodiment of arefrigeration device 10 according to the present invention. Therefrigeration device 10 includes a cabinet 20 having a thermallyinsulated right side wall 22 and a thermally insulated left side wall24, as well as an openable, thermally insulated right door 26 and anopenable, thermally insulated left door 28 providing access to theinterior of the refrigeration device 10. The doors 26, 28 are providedwith gaskets (not shown) to seal the interior of the refrigerationdevice 10 when the doors 26, 28 are closed, and are each provided withgraspable upstanding handles 68 (best seen in FIG. 3) to permit anoperator to open and close each door 26, 28. A pair of lockable, latches40, 42 secure the doors 26, 28 in closed positions, to preventunauthorized access to the contents of the refrigeration device 10. Themechanical components of the refrigeration system for removing heat fromthe interior of the refrigeration device 10 are housed in a compartment30 positioned at the top of the refrigeration device 10. The compartment30 includes a front wall 34 to which is mounted a downwardly directedcontrol display 36 for providing information about the status of therefrigeration device, such as the operating temperature. In addition,several panels 38 are provided for receiving and mounting optionalaccessories, such as a chart recorder that can display the temperaturehistory of the interior of the refrigeration device 10. A cover 80 and aright side wall 82 and a left side wall 84 are provided for enclosingthe compartment 30.

FIG. 2 is perspective view of the refrigeration device 10 of FIG. 1,shown from the lower right, with the doors 26, 28 removed to show theinterior of the refrigeration device 10. The refrigeration deviceincludes a bottom wall or floor 46 as well as a rear wall 48. The sidewalls 22, 24, bottom wall 46 and rear wall 48, and doors 26, 28 (FIG. 1)enclose a first or right interior refrigerated space 50 and second orleft interior refrigerated space 52 of five sides when the doors 26, 28are closed. An upper wall 62 encloses the interior spaces 50, 52 above.Each of the walls 22, 24, 46 and 62 and the doors 26, 28 are preferablythermally insulated, such as, for example, by filing with polyurethanefoam, extruded polystyrene panels, vacuum panels, or the like.

Cold air is provided to the interior refrigerated spaces 50, 52 througha central refrigerated air supply plenum 54 which is provided with aplurality of refrigerated air supply vents 56 for fluid communicationwith both the right interior refrigerated space 50 and the left interiorrefrigerated space 52.

Warm air is returned from the right interior refrigerated space 50 andleft interior refrigerated space 52 through a pair of warm air returnplenums 58 mounted at the upper ends of the refrigerated interior spaces50, 52 and below the upper wall 62 (best seen in FIG. 10). Each of thewarm air return plenums 58 is provided with warm air return vents 60.

In this presently preferred embodiment, the right interior refrigeratedspace 50 and the left interior refrigerated space 52 are of equaldimensions and volume, and cold air is supplied to each in equal amount.However, it is understood that while two interior spaces 50, 52 areshown, the interior of the refrigeration device 10 could include only asingle refrigerated interior space, or more than a pair of refrigeratedinterior spaces, with the refrigerated air supply plenum 54 beingmodified to provide refrigerated air to each such space. Further, whilerefrigerated air is being supplied in equal quantities to eitherrefrigerated interior space in the illustrated presently preferredembodiment, the quantity of refrigerated air supplied to eitherrefrigerated interior space can differ, such as, when it is desired tooperate one refrigerated space as a freezer and the other refrigeratedspace as a refrigerator.

FIG. 3 is a perspective view of the refrigeration device 10 as seen fromthe front upper right, with cover 80 of the upper compartment 30 beingremoved to show the interior of the compartment 30. The compartmentincludes a lower wall or floor 72 on which is mounted a compressormodule 100 including a compressor 102 and condenser 104 and a centrallydisposed evaporator module 120 including a thermally insulatingevaporator cover 130 which seals the interior 148 of the evaporatormodule or compartment (FIGS. 7 and 8) from the remainder of the interiorspace of the upper compartment 30. The compressor module 100 and theevaporator module 120 are in fluid communication through pairs ofdry-break couplings 108, 128.

FIG. 4 is a top plan view of the refrigeration device 10 of FIG. 1 shownwith the upper compartment cover removed 80 (FIG. 1) to reveal theinterior of the upper compartment. The compressor module 100 and thegenerally centrally located evaporator module 120 are mechanicallysecured to the floor 72 of the upper compartment 30 and in fluidcommunication with one another through a plurality of refrigerant lines110, 112, 114, 116. The refrigerant lines 110, 112, 114, 116, include afirst refrigerant supply line 110 extending from the condenser 104mounted on the compressor module 100 and connected to a secondrefrigerant supply line 112 mounted on the evaporator module 120, aswell as a first refrigerant return line 114 mounted on the evaporatormodule 120 and connected to a second refrigerant return line 116 mountedon the compressor module 100. The first and second refrigerant supplylines 110, 112 and the first and second refrigerant return lines 114,116 are secured to one another by dry-break couplings 108, 128.

An evaporation pan 118 is provided in the floor of the compressor module100 to receive condensate discharged from the evaporator module 120 whenthe evaporator 122 is defrosted. The outlet of the compressor 102 is influid communication with the inlet of the condenser 104 through acondensate heating line 140 running through the evaporation pan 118. Hotrefrigerant output from the compressor 102 provides heat to any liquidcondensate in the evaporation pan 118 to speed evaporation of the liquidcondensate back into the atmosphere. The condensate is provided from theevaporator module 120 by a drain line 142 extending above theevaporation pan 118.

FIG. 5 is a top plan view of the refrigeration device 10 of FIG. 1 shownwith the cover 80 of the upper compartment 30 removed and thereplaceable evaporator module 120 removed to show the floor 72 of theupper compartment 30 under the evaporator module 120. The floor 72includes a pair of warm air return apertures 74 positioned under theevaporator module 120 so that the warm air return plenum 58 is in fluidcommunication with warm air intakes of the evaporator module 120. Inaddition, the floor 72 includes a centrally disposed cold air supplyaperture 76 positioned under the evaporator module 120 such that therefrigerated air supply plenum 54 is in fluid communication with thecold air supply outlet of the evaporator module 120. Further, the floor72 of the upper compartment 30, which is preferably formed from a highstrength, light weight material, such as a sheet metal, such as steel oraluminum, includes a series of elongated apertures or perforations 78arranged in a generally rectangular shape and positioned immediatelybelow the walls of the evaporator module 120, such that contact betweenthe floor 72 and the evaporator module 120 is substantially reduced. Thevolume between the floor 72 of the upper compartment 30 and the upperwall 62 of the interior spaces is preferably filled with a thermallyinsulative material, and the series of perforations or elongatedapertures 78 in the floor 72 increase the thermal isolation of theevaporator module 120 within the refrigeration device 10.

FIG. 6 is a perspective view of the compressor module 100 of therefrigeration device 10 of FIG. 1 shown removed from the refrigerationdevice 10. The compressor 102 is mounted on the base 150 of thecompressor module 100 vibration-damping feet 152.

FIG. 7 is a perspective view of the evaporator module 120 of therefrigeration device 10 of FIG. 1 shown removed from the refrigerationdevice 10 with the evaporator cover 130 rotated for removal to show theinterior of the evaporator module 120 and the interior detail of thecover 130 of evaporator module 120. The evaporator module 120 includesthe components of the low temperature portion of the refrigerator: theevaporator heat exchanger (a.k.a. “coil”) 125, such as plate-fin andtube style, and the air circulating fan or fans 124. The evaporatormodule 120 includes a generally centrally disposed evaporator 122,supplied with refrigerant fluid from the compressor module 100 throughthe second refrigerant supply line 112 via a dry-break coupling 128 anda capillary or thermal expansion valve 126. Refrigerant fluid returnsfrom the evaporator module 120 to the compressor module 100 through thefirst refrigerant return line 114 via another dry-break coupling 128.The evaporator 122 is mounted on an evaporator module base 144. Anupstanding wall 146 extends generally vertically from the edges of thebase 144 to partially enclose the interior 148 of the evaporator module120. The cover 130 of the evaporator module 120 is shown rotated up andoff the upstanding wall 146 along the dashed line 180 to reveal theinterior of the evaporator module 120. The evaporator module base 144,the upstanding wall 146, and the evaporator cover 130 together comprisean evaporator housing 121. The upper edge 182 of the upstanding wall 146and the lower edge 184 of the cover 130 are adapted to fit tightlytogether in mating and sealing engagement when the cover 130 is affixedto the upstanding wall 146. A snap fit engagement is preferablyprovided. The interior 148 of the evaporator module 120 is divided intoa warm air chamber 160 and a cold air chamber 170 by the evaporator 122and a shroud 132. Air is drawn from the warm air chamber 160 through theevaporator 122 by an evaporator fan 124 and expelled to the cold airchamber 170.

The shroud 132 is formed by a first upstanding lower shroud wall 162 anda second upstanding lower shroud wall 164, each extending upward fromthe base 144 of the evaporator module 120, and a first upper shroud wall166 and a second upper shroud wall 168, each of which extend generallydownward from the underside of the evaporator cover 130. Each of thelower shroud walls 162, 164 matingly engage with a respective uppershroud wall 166, 168 to form an air-tight seal when the evaporator cover130 is mounted on the upstanding wall to seal the warm air chamber 160from the cold air chamber 170.

Centered proximate a first edge of the base 144 of the evaporator module120 is a refrigerated air supply aperture 145 (FIG. 11) which is inregister with the cold air supply aperture 76 formed in the floor 72 ofthe upper compartment 30 to permit refrigerated air from the evaporatormodule 120 to flow through the refrigerated air supply plenum 54 to thefirst refrigerated interior space 50 and the second refrigeratedinterior space 52

Flanking the refrigerated air supply aperture and formed proximatesecond and third edges of the base 144 of the evaporator module 120 arefirst and second warm air return apertures 147 (FIG. 11), each of whichis in register with a respective warm air return aperture 74 formed inthe floor of the upper compartment 72 when the evaporator module 120 ismounted in the refrigeration device 10. The first and second warm airreturn apertures permit warm air from the first refrigerated interiorspace 50 and the second refrigerated interior space 52 to flow throughthe warm air return plenum 58 to the warm air chamber 160.

The upstanding wall, evaporator cover 130, and shroud 132 provide twointegrated evaporator air supply ducts 200, 210 that distribute balancedair from return plenum 58 and direct balanced air flow to evaporator 122and evaporator fan 124

The surfaces of the base of the evaporator module 120, the shroud 132and the interior of the evaporator cover 130, are formed and contouredto minimize the air-side pressure drop through the evaporator 122 inorder to minimize energy consumption and maximize heat transfer from theevaporator fan 124.

Preferably, the air-side pressure drop through the evaporator is no morethan 0.2 inches H₂O, and more preferably no more than 0.1 inches H₂O.Preferably, the overall pressure drop for the air flow side from thecold air supply inlet, through the cabinet of the refrigeration device,through the return air ducting, and up to the face of the evaporatorinlet face, is no more than 0.35 inches H₂O, and more preferably, nomore than 0.25 inches H₂O.

A defrost heater 190 is provided proximate the evaporator 122 to heatthe evaporator coils during defrost cycles in order to melt frostforming on the evaporator coils which otherwise would degrade theperformance of the refrigeration device 10. Melt water from the defrostheater collects in a recess or drain pan formed in the base 144 of theevaporator module 120 and drains out through the drain line 142 to theevaporation pan 118 formed in the condenser module 120.

Preferably, each of the components of the evaporator housing 121,including in particular the removable evaporator cover 130, is formedfrom a thermally insulative material. Preferably, the thermallyinsulative material is an expanded polymeric material. Preferably, theexpanded polymeric material is an expanded polypropylene. Preferably thethermally insulative material has thermal conductivity of less than0.041 W/m-K at 24 degrees C. Preferably, the expanded polymeric materialhas a density of from about 46 to 81 g/L. The polymeric material canoptionally include additives to provide fire retardancy and/orantimicrobial properties. Preferably, the thermally insulating materialis sufficiently elastic to provide a reusable seal without the need forany caulking, sealant, gaskets, or fasteners.

FIG. 8 is another upper perspective view of the evaporator module 120shown in FIG. 7.

FIG. 9 shows a safety feature that ensures the evaporator housing cover130 is securely installed after service is complete. One to fourmechanical switches 136 are provided, one placed at each side of theevaporator housing. Optionally, these switches connect to a LED lightindicator (not shown). When the evaporator cover 130 is properly placedthe LED indicator go off. If the cover is not securely installed the LEDremains on indicating the cover is not fully secure.

Alternatively, electric circuitry is provided (not shown) to connect theswitches 130 to the electronic control (not shown) of the refrigerationdevice 10 such that the refrigeration device 10 will not operate unlessthe switches 136 are closed, thus ensuring that the cover 130 sealinglyengages the upstanding wall 146 to thermally isolate the interior 148 ofthe evaporator module 120 before the refrigeration device 10 can beoperated.

Sensible indications (not shown), such as lamps, or audible devices, canbe provided to signal that the cover 130 has been securely affixed tothe upstanding wall 146.

Secure installation of the evaporator cover 130 is important to theperformance of the refrigeration device 10, therefore having a means toensure the evaporator cover is 130 properly installed is of significantvalue.

The refrigeration device 10 of the present invention can be quicklyserviced. For example, a qualified service technician can access theupper compartment 30 with the help of a step ladder and separate theself-sealing dry break coupling to remove and replace a compressormodule 100 having a failed component in a short period of time, such as30 minutes. Meanwhile, the interior spaces of the refrigeration device10 and the evaporator module 120 remain thermally isolated, protectingthe contents of the refrigeration device against thermal degradation.

Similarly, in the event that there is an evaporator fan 124 failure, orthermal expansion valve 126 failure, or an evaporator coil failure thetechnician would lift off the evaporator housing cover 130 to gainaccess to the failed components. To replace the evaporator module 120the technician would access the self-sealing dry-break couplings. Theevaporator unit can be quickly replaced with a fully-functionalevaporator module 130. The double-door refrigeration device 10 could beoperational within 30 minutes.

Preferably, the refrigeration device 10 includes at least onetemperature sensing device (not shown) for each of the refrigeratedchambers 50, 52 for sensing the temperature of the interior of therefrigeration device 10. Preferably, the refrigeration device 10 isprovided with means for displaying to an observer and/or recording thetemperature sensed by each such sensing device (or some weighted averageor other function thereof). Preferably, the refrigeration device 10 isprovided with at least one alarm providing a sensible indication, suchas a visible or audible indication, when there is a change in theoperating status of the refrigeration device 10, such as when thetemperature has risen above a predetermined upper limit or below lowertemperature, and/or there has been a failure of one of the mechanicalcomponents such as the compressor 102, the condenser fan 106, theevaporator fan 124, and/or there has been a power failure. In addition,or alternatively, the refrigeration device 10 can be provided with anInternet connection so that the status of refrigeration device 10(including the sensed temperature(s) of the interior, the set limittemperatures for the alarms, etc.) can be remotely monitored and/orcontrolled.

The refrigeration device 10 also preferably includes electronic control(not shown) for controlling operation of the mechanical components ofthe refrigeration system.

Air circulation within the refrigeration device 10 is illustrated inFIGS. 11 and 12. Warm air (schematically depicted by the arrows 220) isdrawn from the first and second refrigerated interior spaces 50, 52through the warm air return plenums (FIG. 12) and up through warm airsupply apertures 147 in the base 144 of the evaporator module 120 intothe warm air chambers 160 (FIG. 11). The warm air 220 is then drawnthrough the evaporator 122 where it is cooled, to provide cold air(schematically depicted by the arrows 230). The cold air 230 is pushedout of the evaporator module 120 by the evaporator fan 124 and into therefrigerated air supply plenum 54 and out through the refrigerated airsupply vents 56 into the first and second interior spaces 50, 52.

Various modifications can be made in the details of the variousembodiments of the refrigeration device of the present invention, allwithin the scope and spirit of the invention and defined by the appendedclaims.

1. A refrigeration device comprising: a) a cabinet having a first and asecond refrigerated interior space; b) the cabinet including acompartment; c) an air supply plenum positioned between the first andthe second refrigerated spaces; d) the compartment including acompressor module and an evaporator module, with a refrigerant fluidcirculating between the compressor module and the evaporator module; e)the air supply plenum being adapted to provide air from the evaporatormodule to the first and the second refrigerated spaces; f) theevaporator module including an evaporator and at least one fan forcirculating air from the evaporator through the plenum; g) theevaporator module being removable from the refrigeration device; h) theevaporator module including a removable cover; i) the compressor modulebeing removable from the refrigeration device; j) at least one returnair plenum for collecting air from the first and the second refrigeratedspaces.
 2. A refrigeration device according to claim 1 wherein thecompartment is positioned above the first and second refrigeratedinterior spaces.
 3. A refrigeration device according to claim 1 whereinthe compartment is positioned below the first and the secondrefrigerated spaces.
 4. A refrigeration device according to claim 1wherein the removable cover is formed from a thermally insulativematerial.
 5. A refrigeration device according to claim 1 wherein therefrigerant is circulated between the compressor module and theevaporator module through self-sealing dry-break couplings.
 6. Arefrigeration device according to claim 1 wherein the evaporator moduleincludes a shroud over the evaporator to prevent air returning from thefirst and second refrigerated spaces from bypassing the evaporator.
 7. Arefrigeration device according to claim 1 wherein the evaporator moduleincludes return air supply ducts to provide balanced air from at leastone return air plenum to the evaporator.
 8. A refrigeration deviceaccording to claim 7 wherein the interior surfaces of the return airsupply ducts and the removable cover are contoured to facilitate lowair-side pressure drop.
 9. A refrigeration device according to claim 1,wherein the evaporator module includes an upstanding partial enclosurefor mating and sealing engagement with the removable cover.
 10. Arefrigeration device according to claim 9, wherein the compartmentincludes a mounting surface for the compressor module and the evaporatormodule, the upstanding partial enclosure of the evaporator modulecontacting the mounting surface and defining a contact area, themounting surface being partially perforated in the vicinity of thecontact area to enhance the thermal isolation of the evaporator module.11. A refrigeration device according to claim 1, further including atleast one switch indicating when the cover is not securely fastened. 12.A double door refrigeration device comprising: a) a cabinet having afirst and a second refrigerated interior space; b) the cabinet includinga compartment for enclosing a refrigeration system including acompressor, a condenser, and an evaporator; c) an air supply plenumpositioned between the first and the second refrigerated spaces; e) theair supply plenum being adapted to provide air from the evaporator tothe first and the second refrigerated spaces; f) at least one return airplenum for collecting air from the first and the second refrigeratedspaces and returning the air to the evaporator.
 13. A refrigerationdevice according to claim 12 wherein the compartment is positioned abovethe first and second refrigerated interior spaces.
 14. A refrigerationdevice according to claim 11 wherein the compartment has an interior,the evaporator being positioned in a thermally insulative housing withinthe compartment.
 15. A refrigeration device according to claim 14wherein the housing includes a removable cover.
 16. A refrigerationdevice according to claim 15 wherein the housing includes a shroud overthe evaporator to prevent air returning from the first and secondrefrigerated spaces from bypassing the evaporator.
 17. A refrigerationdevice according to claim 14 wherein the housing includes return airsupply ducts to provide balanced air from at least one return air plenumto the evaporator.
 18. A refrigeration device according to claim 17wherein the interior surfaces of the return air supply ducts and theremovable cover are contoured to facilitate low air-side pressure drop.19. A refrigeration device according to claim 14, wherein the housingincludes an upstanding partial enclosure for mating and sealingengagement with the removable cover.
 20. A refrigeration deviceaccording to claim 19, wherein the compartment includes a mountingsurface for the compressor and the housing, the upstanding partialenclosure of the housing contacting the mounting surface and defining acontact area, the mounting surface being partially perforated in thevicinity of the contact area to enhance the thermal isolation of theevaporator.
 21. A self-contained evaporator module for use with arefrigeration device, the evaporator module including: a) an evaporatormodule housing having an interior and an evaporator; b) at least oneevaporator fan for drawing or pushing air through the evaporator to coolthe air flowing through the evaporator; wherein the evaporator modulehousing preferably includes: an evaporator module base and an evaporatormodule cover, the evaporator module base and evaporator module coverfitting together tightly to provide a seal against air flow between theinterior of the evaporator module and the exterior, the evaporatormodule cover being formed from a thermally insulating material, theinterior of the evaporator module being divided into a warm air chamberand a cold air chamber, the warm air chamber and the cold air chamberbeing separated by at least one interior wall formed in the housing andby the evaporator.